114E-14 |
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E.-S. HWANG, Center for Agricultural Biomaterials, Seoul National University, San 56-1, Shillim-dong, Kwanak-gu, Seoul, South Korea and T. W. Moon, Department of Food Science and Technology, Seoul National University, School of Agricultural Biotechnology, San 56-1, Shillim-dong, Kwanak-gu, Seoul, 151-742, South Korea. Saponins are naturally occurring glycosidic compounds present in edible and inedible plants. Soybeans are one of the major sources of saponin. Saponins have been reported to possess several health benefits including hypocholesterolemic, immune-stimulatory and anticarcinogenic activities. Phase II detoxification enzymes such as quinone reductase (QR) compete with phase I enzymes to limit the generation of electrophiles, thus reducing the risk of cancer initiation. Therefore, the maintenance of elevated levels of phase II enzymes in body tissues protects the body against highly reactive electrophiles. The objectives of this study were to determine if soysaponin is a radical scavenger and inducer of QR in Hepa1c1c7 murine hepatoma cells. Semi-purified soysaponins were prepared from a commercial crude saponin, a fine yellow-brown powder. The purity of saponin was determined by LC/MS. Antioxidant activity of soysaponin was evaluated using the 1,1'-diphenyl-2-picrylhydrazyl (DPPH) and 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical scavenging methods. Antioxidant capacity of soysaponin was compared with other antioxidants (ascorbic acid, a-tocopherol, and BHT). Hepa1c1c7 mouse hepatoma cells were grown in a-MEM supplemented with 10% heat-inactivated fetal bovine serum. After 24 h of incubation, cells were treated with medium containing the test compounds and determined cell viability and QR activity. Antioxidant activity of the tested compounds decreased in the following order: ascorbic acid > BHT > a-tocopherol > soysaponin. Soysaponin showed 51% radical scavenging activity in the DPPH assay and 65% in the ABTS method at 25 mg/mL concentration. Soysaponin inhibited cell growth in a dose-dependent (0.1-1,000 mg/mL) manner and growth inhibition was 23% and 55% at 30 mg/mL and 250 mg/mL of saponin, respectively after 24 hr incubation. Soysaponin showed QR induction as a dose-dependent manner, showing 0.1, 0.5 and 1 mg/mL of soysaponin caused a 1.6-, 2.2- and 2.9-fold induction of QR, respectively. These results provide a basis for potential of soysaponin as a chemopreventive agent.
Session 114E, Nutraceuticals & Functional Foods: Bioactivity measurement and mechanism
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